<!DOCTYPE HTML>
<html>
<body style="overflow:hidden; height:3000px">
  <div style="position:absolute; top:-25px; left:0; width:100px; height:200px; background:yellow; z-index:1"></div>
  <div style="position:fixed; background:blue; top:0; left:0; width:200px; height:100px">
    <div style="position:absolute; background:cyan; top:40px; left:0; width:50px; height:300px;"></div>
  </div>
</body>
</html>
